The picture is by Maxy, and the text is taken from the latest issue of the Entomological Livestock Group Newsletter:Thanks to all the ELG members who helped us to our research into parasitoids of Small Tortoiseshell and Peacock butterflies in 2008. Our research focused particularly on the arrival and spread of a 'new' tachnid fly, Sturmia bella, from the continent since 1998. We would like to ask for your help again in 2009 as our research continues. Some of the data from the 2008 are still being analysed, but a report of the main results can now be downloaded from our web site at the following address:
- To summarise:
* Small Tortoiseshells have declined by approximately 50% in the past decade
* Sturmia bella now has a wide distribution in southern Britain, at least as far north as Merseyside and Doncaster.
* Small Tortoiseshells have declined most dramatically in southern Britain but have
been declining in northern England and Scotland too.
been declining in northern England and Scotland too.
* Sturmia bella is now the major parasitoid for Small Tortoiseshells (but not Peacocks)
* Sturmia bella is mostly recorded from caterpillars collected in late summer.
* Sturmia bella is an additional cause of mortality to the larval batches it parasitizes and may now be competing with native parasitoids.
* The overwintering strategy of Sturmia bella in the UK is still unknown.
* There is no evidence that local decline rates reflect the presence of Sturmia bella, but sample sizes are small.
Caterpillar samples of Peacock or Small Tortoiseshell collected from the same location as last
year would be extremely valuable, but we are also interested in samples from new sites. Samples from northern England and Scotland would be especially welcome.
year would be extremely valuable, but we are also interested in samples from new sites. Samples from northern England and Scotland would be especially welcome.
Instructions and recording sheets (slightly updated since last year) are available at the project web site. Dr Owen Lewis & Dr Sofia Gripenberg, Department of Zoology, University of Oxford (Email: sturmia.bella@googlemail.com )
No comments:
Post a Comment